Solve for $x$ and $y$ using substitution. ${3x+3y = 0}$ ${x = -6y-5}$
Explanation: Since $x$ has already been solved for, substitute $-6y-5$ for $x$ in the first equation. ${3}{(-6y-5)}{+ 3y = 0}$ Simplify and solve for $y$ $-18y-15 + 3y = 0$ $-15y-15 = 0$ $-15y-15{+15} = 0{+15}$ $-15y = 15$ $\dfrac{-15y}{{-15}} = \dfrac{15}{{-15}}$ ${y = -1}$ Now that you know ${y = -1}$ , plug it back into $\thinspace {x = -6y-5}\thinspace$ to find $x$ ${x = -6}{(-1)}{ - 5}$ $x = 6 - 5$ ${x = 1}$ You can also plug ${y = -1}$ into $\thinspace {3x+3y = 0}\thinspace$ and get the same answer for $x$ : ${3x + 3}{(-1)}{= 0}$ ${x = 1}$